Fabric roofing material



UNITED STATES PATENT OFFICE.

RUFUS S. MERRILL, OF WAKEFIELD, MASSACHUSETTS.

FAB-RIC ROOFING MATERIAL.

SPECIFICATION forming part of Letters Patent No. 437,033, dated September 23, 1890.

Application filed December 24, 1889. Serial No. 384,847. (No specimens.)

To aZZ whom it may. concern.-

Be it known that I, RUFUS S. MERRILL, of Wakefield, in the county of Middlesex and State of Massachusetts, have invented certain new and useful Improvements in Fabric Roofing Material, of which the following is a specification.

My invention relates to that class of roofing material usually known as fabric roofing.

The roofing material made by me consists of a woven or textile fabric or felted cloth saturated with and covered on both sides by coal-tar or the likesuch as pine-tar, in which has been incorporated infusorial or diatomaceous earth in sufficient quantity to produce a cement which will render the cloth waterproof and practically fire-proof. It is this feature which mainly characterizes my invention. The coal-tar or the like waterproof the cloth and prevents decay, while the infusorial earth keeps the material from being ignited by sparks, 850., thus rendering it practically fire-proof. This infusorial earth not only is very cheap, but is comparatively much lighter than other materials heretofore used for analogous purposes, (for example, abarrel of such earth weighing seventy pounds as against a like-sized barrel of powdered soapstone, which will weigh about two hundred and fifty pounds,) and is most efficient in the connection in which it is used.

Varying proportions of the tar and in'fusorial earth can be used, and I do not desire to be understood as limiting myself to any specific proportions. In practice I find that very good results are obtained by taking twentyfive parts of the infusorial earth to seventyfive parts of the tar. {These ingredients are thoroughly mixed together, and by the application of heat the mixture is brought to the fluid consistency suitable for a bath in which the fabric can be treated. The cloth or fabric is drawn through this bath and the excess of liquid composition is squeezed out from it afterwards by passing it between pressurerolls. I then pass the cloth thus treated through what may be called a dust bath, com posed of pulverulent infusorial earth, which adheres to the treated cloth. The latter is then hung up, and as soon as the infusorial dust thus applied has absorbed all of the liquid tar it can the dust bath is repeated, and so on until the desired absorption of the liquid tar has been obtained. Usually two applications of the dust bath will suffice. After the cloth has been thus finished and is ready for the market I roll it up in rolls, and while doing this I sift or spread over the surface a coating of powdered absorbing material, which preferably is the diatomaceous earth already referred to, but, if desired, may be soapstone, plumbago, clay, slatestone, silicate, magnesia, or similar substance in sufficient quantity to prevent the layers from sticking together. This coating I roll up with the cloth, where it is held in place by the com pactness of the roll, thus enabling those who afterwards use the roll to unroll it easily, and at the same time to handle it and put it down on the roof without sticking up or soiling the hands. This last feature is applicable generally to fabric roofing treated with sticky compositions having a tarry base.

I am aware that porous paper has been coated on one side first with a liquid or semiliquid layer or a composition composed of asbestus, soapstone, and coal-tar, and next with a layer of dry asbestus or soapstone, or both, the two layers, together with the backing of porous paper, being subsequently compacted by pressure.

I am also aware that a composition felting has been made by saturating a bat of animal or vegetable fibers with a composition of oil, rosin or pitch, and mineral substances or silica. I claim neither one of these things.

VVha-t I do claim, and desire to secure by Letters Patent, is

As a new article of manufacture, a roofing material composed of a fabric saturated and. covered on both sides by a flexiblecementcomposed essentially of infusorial or diatomaceous earth and coal-tar or the like, substantially as hereinbefore set forth.

In testimony whereof I have hereunto set my hand this 23d day of December, 1889.

RUFUS S. MERRILL. 

